Method and apparatus for performing arthroscopic microfracture surgery

ABSTRACT

A microfracture instrument for applying microfracture therapy to a bone, the microfracture instrument comprising:
         an elongated shaft comprising a distal end and a proximal end;   a needle comprising a body terminating in at least one sharp point, the needle being movably mounted to the distal end of the shaft for movement between an extended position for engaging the bone with the at least one sharp point of the needle and a retracted position for withdrawing the at least one sharp point of the needle from the bone; and   a drive shaft movably mounted to the elongated shaft, the drive shaft being connected to the body of the needle so that movement of the drive shaft relative to the elongated shaft moves the needle between its extended position and its retracted position.

REFERENCE TO PENDING PRIOR PATENT APPLICATION

This patent application claims benefit of pending prior U.S. ProvisionalPatent Application Ser. No. 61/126,911, filed May 8, 2008 by ChrisPamichev et al. for METHOD AND APPARATUS FOR PERFORMING ARTHROSCOPICMICROFRACTURE SURGERY, which patent application is hereby incorporatedherein by reference.

FIELD OF THE INVENTION

This invention relates to methods and apparatus for performingorthopedic surgery in general, and more particularly to methods andapparatus for performing arthroscopic microfracture surgery.

BACKGROUND OF THE INVENTION

Articular cartilage is a smooth, resilient tissue which covers theopposing ends of bones and facilitates the smooth movement of the bonesrelative to one another. However, when articular cartilage is damaged(e.g., through injury or prolonged wear), subsequent motion of the bonestends to increase that damage, ultimately causing the cartilage to wearaway completely. When this occurs, the bones rub directly against oneanother, typically resulting in substantial pain for the patient andreduced mobility of the joint. In many cases, such damage to articularcartilage can lead to osteoarthritis.

Microfracture surgery is an orthopedic procedure which can help torestore articular cartilage. More particularly, microfracture surgerycreates tiny fractures in the cortical bone bed disposed immediatelybelow the damaged articular cartilage. These fractures permit blood andbone marrow to seep out of the underlying cancellous bone andessentially create blood clots which release cartilage-building cells.These cartilage-building cells then result in the formation ofreplacement cartilage.

To date, microfracture surgery is typically performed using a small,sharp pick or awl to create the small microfracture holes in thecortical bone. However, such picks or awls are generally used by drivingthem longitudinally, e.g., with a hammer or mallet, thereby requiringsubstantially direct linear access to the bone surface which is toreceive the microfracture therapy. Furthermore, where the microfracturemust be created in a bone surface which is not substantially alignedwith the angle of access, it can be difficult to generate the forcesrequired for the pick or awl to penetrate the hard cortical bone andrelease blood and bone marrow from the underlying cancellous bone.

In many cases, e.g., certain sites on the lower femur, such directlinear access to the microfracture site may be readily available.However, in other cases, intervening anatomical structures may make itdifficult or impossible to use a conventional pick or awl to perform themicrofracture surgery on the bone. This is particularly true where themicrofracture surgery is to be performed arthroscopically. By way ofexample but not limitation, it can be difficult or even impossible toarthroscopically perform microfracture therapy on the acetabular cup ofthe hip using a conventional pick or awl, given the anatomicalconstraints typically imposed in arthroscopic hip surgery.

The present invention is intended to provide a novel method andapparatus for performing arthroscopic microfracture surgery,particularly in locations where it is difficult to utilize aconventional pick or awl in the microfracture surgery.

SUMMARY OF THE INVENTION

The present invention provides a novel method and apparatus forperforming arthroscopic microfracture surgery. The novel apparatuspermits the microfracture therapy to be applied to a bone surface evenwhere that bone surface is set at an angle to the axis of approachand/or where it might otherwise be difficult or impossible to use aconventional pick or awl to perform the microfracture surgery.

In one form of the present invention, there is provided a microfractureinstrument for applying microfracture therapy to a bone, themicrofracture instrument comprising:

an elongated shaft comprising a distal end and a proximal end;

a needle comprising a body terminating in at least one sharp point, theneedle being movably mounted to the distal end of the shaft for movementbetween an extended position for engaging the bone with the at least onesharp point of the needle and a retracted position for withdrawing theat least one sharp point of the needle from the bone; and

a drive shaft movably mounted to the elongated shaft, the drive shaftbeing connected to the body of the needle so that movement of the driveshaft relative to the elongated shaft moves the needle between itsextended position and its retracted position.

In another form of the present invention, there is provided amicrofracture instrument for applying microfracture therapy to a bone,the microfracture instrument comprising:

an elongated shaft comprising a distal end and a proximal end;

a needle comprising a body terminating in at least one sharp point, theneedle being mounted to the distal end of the shaft; and

a drive shaft movably mounted to the elongated shaft, the drive shaft isadapted to move radially relative to the elongated shaft in order tostrike the needle and engage the bone.

In another form of the present invention, there is provided amicrofracture instrument for applying microfracture therapy to a bone,the microfracture instrument comprising:

an elongated shaft comprising a distal end and a proximal end;

a needle comprising a body terminating in at least one sharp point, theneedle being mounted to the distal end of the shaft; and

a drive shaft movably mounted to the elongated shaft, the drive shaft isadapted to move rotationally relative to the elongated shaft in order torotate the needle to engage the bone.

In another form of the present invention, there is provided a method forapplying microfracture therapy to a bone, the method comprising:

providing a microfracture instrument comprising:

-   -   an elongated shaft comprising a distal end and a proximal end;    -   a needle comprising a body terminating in at least one sharp        point, the needle being movably mounted to the distal end of the        shaft for movement between an extended position for engaging the        bone with the at least one sharp point of the needle and a        retracted position for withdrawing the at least one sharp point        of the needle from the bone; and    -   a drive shaft movably mounted to the elongated shaft, the drive        shaft being connected to the body of the needle so that movement        of the drive shaft relative to the elongated shaft moves the        needle between its extended position and its retracted position;

positioning the elongated shaft adjacent to the bone; and

moving the drive shaft so that the sharp point of the needle engages thebone.

In another form of the present invention, there is provided a method forapplying microfracture therapy to a bone, the method comprising:

providing a microfracture instrument comprising:

-   -   an elongated shaft comprising a distal end and a proximal end;    -   a needle comprising a body terminating in at least one sharp        point, the needle being mounted to the distal end of the shaft;        and    -   a drive shaft movably mounted to the elongated shaft, the drive        shaft is adapted to move radially relative to the elongated        shaft in order to strike the needle and engage the bone;

positioning the elongated shaft adjacent to the bone; and

moving the drive shaft so that the sharp point of the needle engages thebone.

In another form of the present invention, there is provided a method forapplying microfracture therapy to a bone, the method comprising:

providing a microfracture instrument comprising:

-   -   an elongated shaft comprising a distal end and a proximal end;    -   a needle comprising a body terminating in at least one sharp        point, the needle being mounted to the distal end of the shaft;        and    -   a drive shaft movably mounted to the elongated shaft, the drive        shaft is adapted to move rotationally relative to the elongated        shaft in order to rotate the needle to engage the bone;

positioning the elongated shaft adjacent to the bone; and moving thedrive shaft so that the sharp point of the needle engages the bone.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects and features of the present invention will bemore fully disclosed or rendered obvious by the following detaileddescription of the invention, which is to be considered together withthe accompanying drawings wherein like numbers refer to like parts, andfurther wherein:

FIGS. 1-10 are schematic views showing a first microfracture instrumentformed in accordance with the present invention;

FIGS. 11-15 are schematic views showing a second microfractureinstrument formed in accordance with the present invention;

FIGS. 16-18 are schematic views showing a third microfracture instrumentformed in accordance with the present invention;

FIGS. 19-21 are schematic views showing a fourth microfractureinstrument formed in accordance with the present invention;

FIG. 22 is a schematic view showing a fifth microfracture instrumentformed in accordance with the present invention;

FIGS. 23-34 are schematic views showing a sixth microfracture instrumentformed in accordance with the present invention;

FIG. 35 is a schematic view showing a distal end of another form ofneedle; and

FIGS. 36A, 36B, 37A, 37B, 38 and 39 are schematic views showing aseventh microfracture instrument formed in accordance with the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention comprises the provision and use of novel apparatusfor performing arthroscopic microfracture surgery. The novel apparatuspermits the microfracture therapy to be applied to a bone surface evenwhere that bone surface is set at an angle to the axis of approachand/or where it might otherwise be difficult or impossible to use aconventional pick or awl to perform the microfracture surgery.

More particularly, and looking now at FIGS. 1-5, there is shown a novelmicrofracture instrument 5 formed in accordance with the presentinvention.

Microfracture instrument 5 generally comprises a hollow shaft 10(FIG. 1) having a distal end 15, a proximal end 20, and a lumen 25 (FIG.3) extending therebetween. Distal end 15 of hollow shaft 10 has anopening 30 (FIG. 3) formed therein. The longitudinal axis 35 of opening30 is set at an acute angle to the longitudinal axis 40 of hollow shaft10. Preferably, distal end 15 of hollow shaft 10 also has an opening 45formed therein. Preferably opening 45 is aligned with opening 30 alonglongitudinal axis 35. A handle 47 (FIG. 1) is secured to hollow shaft 10near the proximal end of the shaft.

A shoulder 50 is formed on the inside wall of hollow shaft 10, proximalto openings 30 and 45. A stop 55, having a central opening 60 formedtherein, is disposed within lumen 25 so that the stop engages shoulder50. A spacer tube 65, having a lumen 70 extending therethrough, isdisposed within lumen 25 of hollow shaft 10 so as to capture stop 55against shoulder 50. An end cap 75 (FIG. 5), having a lumen 80 extendingtherethrough, captures spacer tube 65 within lumen 25.

A drive shaft 85 is movably disposed within hollow shaft 10. Moreparticularly, drive shaft 85 comprises a distal end 90 having a diametersized to be slidably received within central opening 60 in stop 55, anda proximal end 95 sized to be slidably received within spacer tube 65and end cap 75. An annular shoulder 100 is disposed intermediate driveshaft 85. Annular shoulder 100 engages stop 55 so as to limit distalmovement of drive shaft 85. See FIGS. 3 and 4.

A drive head 105 is disposed on the distal end of drive shaft 85. Abifurcated seat 110 is disposed on the distal end of drive head 105.More particularly, bifurcated seat 110 comprises a pair of spaced arms115 which are disposed at a right angle to the longitudinal axis 35 ofopening 30. A needle 120, terminating in a sharp distal tip 125 and aproximal flanged head 130, is slidably mounted in bifurcated seat 110,with the shank 132 of needle 120 received between spaced arms 115. As aresult of this construction, proximal and distal movement of drive shaft85 along longitudinal axis 40 causes needle 120 to be retracted into, orprojected out of, opening 30 of hollow shaft 10 along longitudinal axis35. Thus, microfracture instrument 5 can be advanced to a surgical sitealong longitudinal axis 40, yet deliver its needle 120 for microfracturetherapy along a different longitudinal axis 35. This is a significantimprovement over the prior art.

A spring 135 is disposed between drive head 105 and stop 55.

In one form of the invention, spring 135 is a tension spring, so thatdrive shaft 85 is normally biased proximally within hollow shaft 10, andso that needle 120 normally has its sharp distal point 125 in itsretracted position wherein the sharp distal point 125 lies within anaxial projection of the outer perimeter of hollow shaft 10. See FIG. 3.However, the proximal end of drive shaft 85 may be moved distally (e.g.,by tapping it with a hammer or mallet) so that needle 120 has its sharpdistal point 125 in its projected position wherein the sharp distalpoint 125 projects beyond an axial projection of the outer perimeter ofhollow shaft 10. See FIG. 4. In this way, needle 120 can be used toscore a bone in a microfracture procedure. Thus, with this form of theinvention, microfracture instrument 5 may be advanced to the surgicalsite along longitudinal axis 40 with the sharp distal point of needle120 safely retracted inboard of the instrument, and then the proximalend of drive shaft 85 struck with a hammer or mallet so as to drive thesharp distal point of needle 120 along longitudinal axis 35 so as todeliver microfracture therapy to a bone.

In another form of the invention, spring 135 is a compression spring, sothat drive shaft 85 is normally biased distally within hollow shaft 10,and so that needle 120 normally has its sharp distal point 125 in itsprojected position wherein the sharp distal point 125 projects beyond anaxial projection of the outer perimeter of hollow shaft 10. See FIG. 4.However, the proximal end of drive shaft 85 may be moved proximally(e.g., by gripping it manually and pulling it proximally) so that needle120 has its sharp distal point 125 in its retracted position wherein thesharp distal point 125 lies within an axial projection of the outerperimeter of hollow shaft 10. See FIG. 3. Thereafter, when a bone is tobe scored, the proximal end of drive shaft 85 is released, causingcompression spring 125 to drive needle 120 out of the distal end ofhollow shaft 10 and into the bone. Alternatively, the proximal end ofdrive shaft 85 can be released, so that needle 120 projects out ofhollow shaft 10 so that the surgeon can position it on the bone, andthen the proximal end of the drive shaft 85 struck (e.g., with a hammeror mallet) so as to drive sharp distal point 125 into bone. Thus, withthis form of the invention, microfracture instrument 5 may have itsdrive shaft 85 pulled proximally by hand and then the instrumentadvanced to the surgical site along longitudinal axis 40 with the sharpdistal point of needle 120 safely retracted inboard of the instrument,and then the proximal end of drive shaft 85 may be released (and/orstruck with a hammer or mallet) so as to drive the sharp distal point ofneedle 120 along its longitudinal axis 35 so as to deliver microfracturetherapy to a bone.

As seen in FIGS. 1-4 and 6-9, hollow shaft 10 can be formed with amodular construction so that different distal tip configurations can beaccommodated. More particularly, in this form of the invention, hollowshaft 10 can comprise a distal segment 140 which selectively attaches toa proximal segment 145. Distal segment 140 can have its openings 30 and45 set at various angles relative to the longitudinal axis of hollowshaft 10 so as to accommodate a range of surgical applications. In otherwords, longitudinal axis 35 of openings 30 and 45 can be set at variousangles (e.g., 30°, 60°, etc.) to the longitudinal axis 40 of hollowshaft 10. In some embodiments, the angle is greater than 90°, as shownin FIG. 9. In this situation, the drive shaft may be pulled in theproximal direction to drive the needle into the bone. The proximalportion of the device is the same, except that it is configured to drivethe needle in a retrograde fashion, and the reusable portion is designedfor the desired retrograde angle. Furthermore, if desired, distalsegment 140 can be made disposable and proximal segment 145 can be madereusable.

Looking next at FIGS. 10-15, there is shown another novel microfractureinstrument 150 formed in accordance with the present invention.Microfracture instrument 150 is similar to the novel microfractureinstrument 5 discussed above, except as will hereinafter be discussed infurther detail. More particularly, novel microfracture instrument 150generally comprises a hollow shaft 155 (FIG. 11) having a distal end160, a proximal end 165, and a lumen 170 extending therebetween. Distalend 160 of hollow shaft 155 has an opening 175 formed therein. Thelongitudinal axis 180 of opening 175 is set at an acute angle to thelongitudinal axis 185 of hollow shaft 170. Preferably, distal end 165 ofhollow shaft 155 also has an opening 190 formed therein. Preferablyopening 190 is aligned with opening 175 along longitudinal axis 180.

A drive shaft 195 is movably disposed within hollow shaft 155. Driveshaft 195 comprises a distal end 200 having a diameter sized to besecured to a drive head 205, and a proximal end 210 sized to be slidablyreceived within an opening 212 (FIG. 10) formed in an end cap 215. Anannular shoulder 220 (FIG. 11) is disposed intermediate drive shaft 195.

Drive head 205 is disposed on the distal end of drive shaft 195. Anangled surface 225 is disposed at a right angle to the longitudinal axis180 of opening 175. A needle 230, terminating in a sharp distal tip 235and a proximal flanged head 240, is slidably mounted in openings 175 and190. A spring 245 (FIG. 12) biases needle 230 in its retracted position,wherein the sharp distal point 235 of needle 230 lies within an axialprojection of the outer perimeter of hollow shaft 155. As a result ofthis construction, proximal and distal movement of drive shaft 195 alonglongitudinal axis 185 causes needle 230 to be retracted into, orprojected out of, opening 175 of hollow shaft 155 along longitudinalaxis 180. Thus, microfracture instrument 150 can be advanced to asurgical site along longitudinal axis 185, yet deliver its needle 230for microfracture therapy along a different longitudinal axis 180. Thisis a significant improvement over the prior art.

A slot 250 (FIG. 12) formed in drive head 205 cooperates with a pin 255set in hollow shaft 155 so as to limit distal and proximal movement ofdrive shaft 195. See FIGS. 12 and 15.

A spring 260 is disposed between drive head 205 and shoulder 220. Spring260 pushes drive shaft 195 and drive head 205 away from each other, yetallows them to move relative to one another. Spring 260 creates tensionbetween the said parts for the purpose of multiplying the strength ofthe “tap” coming from drive shaft 195 when applied onto drive head 205.Components 260, 195 and 205 move together in direction from proximal endto distal end with each “tap” applied on shaft 210.

In one form of the invention, spring 260 is a tension spring, so thatdrive shaft 195 is normally biased proximally within hollow shaft 155,and so that needle 230 normally has its sharp distal point 235 in itsretracted position wherein the sharp distal point 235 lies within anaxial projection of the outer perimeter of hollow shaft 155. See FIG.11. However, the proximal end of drive shaft 195 may be moved distally(e.g., by tapping it with a hammer or mallet) so that needle 230 has itssharp distal point 235 in its projected position wherein the sharpdistal point 235 projects beyond an axial projection of the outerperimeter of hollow shaft 155. See FIG. 15. In this way, needle 230 canbe used to score a bone in a microfracture procedure. Thus, with thisform of the invention, microfracture instrument 150 may be advanced tothe surgical site along longitudinal axis 185 with the sharp distalpoint of needle 230 safely retracted inboard of the instrument, and thenthe proximal end of drive shaft 195 struck with a hammer or mallet so asto drive the sharp distal point of needle 230 along its longitudinalaxis 180 so as to deliver microfracture therapy to a bone.

In another form of the invention, spring 260 is a compression spring, sothat drive shaft 195 is normally biased distally within hollow shaft155, and so that needle 230 normally has its sharp distal point 235 inits projected position wherein the sharp distal point projects beyond anaxial projection of the outer perimeter of hollow shaft 155. See FIG.15. However, the proximal end of drive shaft 195 may be moved proximally(e.g., by gripping it manually and pulling it proximally) so that needle230 has its sharp distal point 235 in its retracted position wherein thesharp distal point 235 lies within an axial projection of the outerperimeter of hollow shaft 155. See FIG. 11. Thereafter, when a bone isto be scored, the proximal end of drive shaft 195 is released, causingcompression spring 260 to drive needle 230 out of the distal end ofhollow shaft 155 and into the bone. Alternatively, the proximal end ofdrive shaft 195 can be released, so that needle 230 projects out ofhollow shaft 155 so that the surgeon can position it on the bone, andthen the proximal end of the drive shaft 195 struck (e.g., with a hammeror mallet) so as to drive sharp distal point 235 into bone. Thus, withthis form of the invention, microfracture instrument 5 may have itsdrive shaft 195 pulled proximally by hand and then the instrumentadvanced to the surgical site along longitudinal axis 185 with the sharpdistal point of needle 230 safely retracted inboard of the instrument,and then the proximal end of drive shaft 195 may be released (and/orstruck with a hammer or mallet) so as to drive the sharp distal point ofneedle 230 along its longitudinal axis 180 so as to delivermicrofracture therapy to a bone.

Looking next at FIGS. 16-18, there is shown another novel microfractureinstrument 300 formed in accordance with the present invention. Thisconstruction provides an alternative approach for creating a largeamount of potential energy and then suddenly releasing that potentialenergy to a sharp tip in order to create a small defect in bone for amicrofracture procedure.

Microfracture instrument 300 comprises a housing 305 which includes apalm area 310 and a trigger 315. Trigger 315 pivots at a pin 320 andincludes a guide pin 325 which rides in a guide rail 330 of a pawl 335.Pawl 335 rotates about a pawl pin 340 so a lock tab 345 rests against ashoulder 350 of a drive shaft 355. Trigger 315 is also attached to aspring 360 at connection 365. Spring 360 is also attached to shaft 355proximal of shoulder 350. The distal end of drive shaft 355 isconfigured as a block 370 with a wedge surface 375. Wedge surface 375 isin contact with a needle or punch 380 at a punch wedge surface 385. Thepunch tip 390 is held in the outer tube 395 of housing 305 by a punchspring 400.

In use, and looking now at FIG. 17, trigger 315 is actuated so that itpivots on pin 320 and guide pin 325 rides along guide rail 330. However,pawl 335 does not move at this time, because the radius of movement ofguide pin 325 is the same as the radius of guide rail 330 over thisspan. Since trigger 315 is moving, spring 360 begins to compress againstshoulder 350. Shoulder 350 does not move because lock tab 345 holds itin place.

In FIG. 18, trigger 315 is actuated a little further such that guide pin325 starts to run on a steep part of guide rail 330, which forces pawl335 to rotate about pawl pin 340. This motion lowers lock tab 345 awayfrom shoulder 350, such that shaft 355 is allowed to move distallyquickly, based on the potential energy of compressed spring 360. Withthis action, block 370 and its wedge surface 375 also move distal. Wedgesurface 375 slides against punch wedge 385, pushing it against spring400. As a result, punch 380 (and punch tip 390) shoots out of outer tube395 and into the adjacent tissue (not shown) so as to applymicrofracture therapy to the bone.

When trigger 315 is released, spring 360 is pulled proximally atconnection point 365, which pulls shaft 355 and block 370 allowing thepunch 380 to drop back in to the outer tube 395 with the help of thepunch spring 400.

Looking next at FIGS. 19-21, there is shown another microfractureinstrument 400 formed in accordance with the present invention.Microfracture instrument 400 generally comprises an elongated shaft 405having, at its distal end, a first flexible extension 410 and a secondflexible extension 415. First flexible extension 410 comprises a needle420 having a sharp tip 425 thereon.

As a result of this construction, when second flexible extension 415 ispulled away from first flexible extension 410 (e.g., by pulling on acable 430) and then released, second flexible extension 415 will driveagainst first flexible extension 415 so as to drive sharp tip 425 ofneedle 420 against a bone 435, whereby to provide microfracture therapy.

Looking next at FIG. 22, there is shown another microfracture instrument440 formed in accordance with the present invention. Microfractureinstrument 440 generally comprises an elongated shaft 445. At the distalend of elongated shaft 445 is a needle 450 having a sharp tip 455thereon. The proximal end of elongated shaft 445 is connected to apowered driver 460. Powered driver 460 is adapted to move shaft 445 sothat needle 450 moves towards and away from bone 465. By way of examplebut not limitation, powered driver 460 may comprise an electrical orpneumatic oscillator. An electrical oscillator, for example, may use anultrasonic frequency.

As a result of this construction, when needle 450 is positioned againstbone 465 and powered driver 460 activated, sharp tip 455 of needle 450is driven against bone 465, whereby to provide microfracture therapy.

Looking next at FIGS. 23-25, there is shown another novel microfractureinstrument 505 formed in accordance with the present invention.Microfracture instrument 505 generally comprises a hollow shaft 510having a distal end 515, a proximal end 520, and a side window 525formed adjacent to distal end 515. A pair of holes 527 are formed inhollow shaft 510 adjacent to side window 525. A handle 530 is secured toproximal end 520 of hollow shaft 510. A trigger 535 is pivotallyconnected to handle 530 via a pivot pin 540. An opening 542 is formed inhandle 530 proximal to pivot pin 540, and receives a screw 543 therein,for reasons which will hereinafter be disclosed.

A hollow trigger tube 545 is slidably mounted within hollow shaft 510.Hollow trigger tube 545 comprises a distal end 550, a proximal end 555,and a side opening 560 adjacent to distal end 550. Hollow trigger tube545 includes a laterally projecting section 565 intermediate its sideopening 560. A notch 567 is formed at the distal end of trigger tube545. A pair of screws 570 (only one of which is seen in FIG. 23)connects the proximal end of hollow trigger tube 545 to trigger 535. Byway of example but not limitation, the top end of trigger 535 may bebifurcated, and each upper leg of the trigger may be connected to hollowtrigger tube 545 via one screw 570. A compression spring 575 iscoaxially mounted on the proximal end of hollow trigger tube 545 and iscaptured between proximal end 520 of hollow shaft 510 and trigger 535.As a result of this construction, compression spring 575 normally biaseshollow trigger tube 545 (and trigger 535) proximally, however, trigger535 may be used (e.g., by depressing the trigger) so as to urge hollowtrigger tube 545 distally.

Still looking now at FIGS. 23-25, microfracture instrument 505 alsocomprises a beam 580. Beam 580 is disposed within side window 525 ofhollow shaft 510 and within side opening 560 of hollow trigger tube 545.The center portion of beam 580 is secured in place via a U-shaped clip585 which extends through holes 527 formed in hollow shaft 510, with oneleg of U-shaped clip 585 being disposed above beam 580 and the other legof U-shaped clip 585 being disposed below beam 580. A sharp pointedneedle 590 projects laterally out of the distal end of beam 580. Anopening 600 is formed in beam 580, proximal to the point where U-shapedclip 585 engages beam 580.

A cocking shaft 605 is slidably mounted within hollow trigger tube 545.Cocking shaft 605 comprises a distal end 610 having a groove 615 formedtherein, and a proximal end 620 having a cocking knob 625 securedthereto. Cocking knob 625 includes a peripheral groove 630 and alaterally-projecting finger 635. Peripheral groove 630 receives the tipof screw 543 therein, whereby to limit longitudinal movement of cockingknob 625, and hence cocking shaft 605, relative to handle 530. Finger635 acts as a visual indicator to show the current rotationaldisposition of cocking shaft 605 within hollow trigger tube 545, as willhereinafter be discussed in further detail.

If desired, an opening 640 may extend through cocking shaft 605 andcocking knob 625, e.g., so as to permit an endoscope to be advancedthrough microfracture instrument 505 and facilitate visualization of thesurgical site. By passing an endoscope through opening 640 inmicrofracture instrument 505, the endoscope and microfracture instrumentcan both use a single arthroscopic portal. This can be helpful invarious situations, e.g., where the anatomy limits the availability(number and placement) of the access portals. Furthermore, by providingan endoscope-receiving opening 640 in the microfracture instrument 505,the endoscope can be automatically positioned relative to the surgicalsite simply by positioning of the microfracture instrument relative tothe surgical site. This can help reduce the number of “hands” needed toperform the arthroscopic microfracture surgery, and can help ensure thatthe endoscope is always properly directed at the surgical field.

If desired, the endoscope can be inserted into opening 640 ofmicrofracture instrument 505 in the operating room, e.g., just prior tothe commencement of the microfracture procedure or even during themicrofracture procedure itself. Alternatively, microfracture instrument505 could be manufactured so that the endoscope is inserted into opening640 before the instrument leaves the factory.

A cocking bar (or wire) 645 connects cocking shaft 605 to beam 580. Moreparticularly, cocking bar 645 comprises a J-shaped element which passesthrough opening 600 in beam 580 and which is secured in groove 615 ofcocking shaft 605. As a result of this construction, rotation of cockingshaft 605 (e.g., applied via cocking knob 625) applies a rotationalforce to the proximal end of beam 580 via the J-shaped cocking bar 645.

It should be appreciated that microfracture instrument 505 may bereusable or disposable.

Furthermore, microfracture instrument 505 may be partially disposable.More particularly, if desired, beam 580, needle 590 and J-shaped cockingbar 645 can be replaced (as a complete subassembly) by simply removingU-shaped clip 585 and installing a replacement sub-assembly (consistingof a new beam 580, a new needle 590 and a new J-shaped cocking bar 645).This approach allows the majority of microfracture instrument 505 to bere-used while still permitting a new subassembly (i.e., a new beam 580,a new needle 590 and a new J-shaped cocking bar 645) to be supplied foreach procedure.

Furthermore, the ability to replace beam 580, a needle 590 and aJ-shaped cocking bar 645 also permits the microfracture instrument 505to be quickly modified for different applications, e.g., where harderbone is to be penetrated, a beam 580 having a greater spring factor canbe employed. Hollow shaft 510 may have two or more sets of holes 527,thereby allowing U-shaped clip 585 to be inserted in multiple positions.This changes the ratio of the length of beam 580 in front of U-shapedclip 585 to the length of beam 580 behind U-shaped clip 585. The resultis a change in total travel of needle 590 and the resulting force itapplies on the bone.

Novel microfracture instrument 505 permits microfracture therapy to bearthroscopically applied to a bone surface, even where that bone surfaceis set at an angle to the axis of approach and/or where it mightotherwise be difficult or impossible to use a conventional pick or awlto perform the microfracture surgery.

The use of microfracture instrument 505 typically starts with theinstrument in its “at rest” condition, i.e., with the distal end of beam580 set in notch 567 of hollow trigger tube 545, trigger 535 released,and cocking knob 625 set so that its finger 635 points down and groove615 of cocking shaft 605 points upward. See FIGS. 23 and 24.

Next, cocking knob 625 is rotated. This in turn causes cocking shaft 605to be rotated. Cocking knob 625 is rotated to the point where its finger635 points upward and groove 615 of cocking shaft 605 faces downward. Asthis occurs, the proximal end of cocking bar 645 (which is disposed ingroove 615 of cocking shaft 605) is also rotated, which applies atorsional force to the proximal end of beam 580, thereby flexing beam580. See FIGS. 26 and 27.

It should be appreciated that, due to the nature and configuration ofbeam 580, and due to the manner in which beam 580 is simultaneouslysupported (i) in its midsection (via engagement with U-shaped clip 585),(ii) at its distal end (via engagement with notch 567), and (iii) at itsproximal end (via J-shaped cocking bar 645 which extends between beamopening 600 and cocking shaft groove 615), the microfracture instrument505 will be in a stable condition when cocking shaft 605 is disposed sothat groove 615 is oriented fully up (FIGS. 23 and 24) or fully down(FIG. 27).

Thus, when cocking knob 625 is rotated to the point where its finger 635points upward and groove 615 of cocking shaft 605 faces downward, themicrofracture instrument will be in a stable condition, with its beam580 flexed so as to store potential energy in beam 580.

At this point, the device is cocked.

Microfracture instrument 505 is then manipulated so that its sharppointed needle 590 is disposed opposite the site of the desiredmicrofracture therapy.

When microfracture instrument 505 is in proper position, trigger 535 isdepressed so that hollow trigger tube 545 moves distally. This actionreleases the distal end of beam 580 from notch 567, thereby permittingflexed beam 580 to straighten, which causes the distal end of beam 580to be driven laterally. As the distal end of beam 580 is drivenlaterally, sharp pointed needle 590 is driven laterally out ofinstrument 505 and into the adjacent bone, whereby to create a desiredmicrofracture. See FIG. 28.

Then trigger 535 may be released. See FIG. 29. When it is desired toform another microfracture, instrument 505 must first be restored to its“at rest” condition, then re-cocked, and finally re-fired.

The instrument is restored to its “at rest” condition by firstre-depressing trigger 535. See FIG. 30. Then cocking knob 625 is rotatedso that its finger 635 is restored to its downward position and groove615 of cocking shaft 605 once again faces upward. This causes beam 580to return to its original condition where the distal end of the beam islowered and the proximal end of the beam is raised. See FIGS. 30-32.Then trigger 535 is released, so that hollow trigger tube 545 movesproximally and the distal end of beam 580 is re-captured within notch567. At this point the instrument has fully returned to its “at rest”condition shown in FIGS. 23 and 24.

The microfracture instrument may then be re-cocked, and thereafterfired, according to the foregoing sequence.

Thus it will be seen that the microfracture instrument of the presentinvention comprises an apparatus which provides the ability to store,and remotely release, controlled amounts of captured kinetic energy. Theprecise amount of energy stored and subsequently released can beregulated by the particular construction of beam 580 (e.g., the choiceof materials used, the configuration of the beam, the dimensions of thebeam, etc.). Furthermore, the amount of energy stored and released couldbe regulated by utilizing an alternative form of cocking mechanism,e.g., one which permits the user to determine the precise amount of beamdeflection used to drive needle 590 (such as a ratchet mechanism). Itwill be appreciated that the approach used by the present invention isfundamentally different from the “hammer hit” pick or awl of currentmicrofracture techniques, since the present invention permits acontrolled amount of energy to be stored and remotely released.

If desired, the distal end of microfracture instrument 505 may be formedwith a flexible configuration. Such a construction can permitmicrofracture instrument 505 to better conform to the particulars of atreatment site or to extend the reach of the instrument without the needto fully distract a joint.

Furthermore, the distal end of shaft 510 can be provided with a locatorneedle extending laterally of the microfracture instrument 505. Thislocator needle can be placed in a previously-placed fracture hole so asto set the location of a subsequent fracture hole. This arrangement canbe used so as to ensure a known spacing between various fracture holes.

Additionally, beam 580 can be provided with more than one needle, thusallowing for the placement of multiple fracture holes with one “firing”of the instrument. Where more than one needle 590 is provided, themultiple needles can be arranged in various configurations, e.g.,linear, crossed, etc.

If desired, beam 580 can be formed with a slight recess on its undersideso as to form a natural seat for J-shaped cocking bar 645 when themicrofracture instrument is placed in its cocked position (FIG. 27).This construction has the advantage that it can provide tactile feedbackto the user when the J-shaped cocking bar 645 seats in the recess,thereby confirming for the user that the microfracture instrument hasbeen placed in its cocked state.

If desired, the needle of the microfracture instrument may be adapted todeliver a therapeutic agent which induces cartilage growth.

Furthermore, it should also be appreciated that the needle of themicrofracture instrument may be configured to provide a plurality ofsharp points. Thus, for example, in FIG. 35, there is shown a needle 700comprising a plurality of sharp points 705 for applying microfracturetherapy to a bone. This configuration can be advantageous where it isdesired to apply a plurality of microfractures with a single impact.

Looking next at FIGS. 36A and 36B, there is shown another novelmicrofracture instrument 805 also formed in accordance with the presentinvention.

Microfracture instrument 805 is intended to penetrate a bone with adrilling action rather than with an impact action as is the case withthe microfracture instruments disclosed above.

To this end, microfracture instrument 805 generally comprises anelongated shaft 810 having an opening 815 formed in its distal end. Abracket 820 is disposed within elongated shaft 810 adjacent to opening815. Bracket 820 serves to rotatably support a drill element 825extending through opening 815. Drill element 825 in turn comprises adrill tip 830 and a geared head 835. Geared head 835 is driven by adrive shaft 840. More particularly, drive shaft 840 has a geared distalend 845 for engaging the geared head 835 of drill element 825.

On account of the foregoing construction, elongated shaft 810 can beused to advance microfracture instrument 805 so that its drill element825 is located adjacent to the bone site which is to be microfractured,and then drive shaft 810 can be rotated so as to turn drill element 825into the bone, whereby to created the desired microfracture. Thisprocess can be repeated as many times as desired until the desireddegree of microfracture has been achieved.

FIGS. 37A, 37B, 38 and 39 show a related construction. Moreparticularly, with the construction shown in FIGS. 36A and 36B, drillelement 825 extends at a fixed angle relative to the longitudinal axisof elongated shaft 810. The construction shown in FIGS. 37A, 37B, 38 and39 allows the angle of the drill element to be adjusted relative to thelongitudinal axis of the elongated shaft.

More particularly, in FIGS. 37A, 37B, 38 and 39 there is shown amicrofracture instrument 850 which has a mount 855 pivotally disposed atits distal end. Mount 855 is pivoted by pushing or pulling on one ormore control rods or lines 860 so as to adjust the angular position ofmount 855 relative to the longitudinal axis of the microfractureinstrument. Microfracture instrument 850 also comprises a drive shaft870 which has a flexible distal end 875 extending through mount 855,such that adjustment of the angular position of mount 855 results inadjustment of the angular position of flexible distal end 875 of driveshaft 870. Flexible distal end 875 of drive shaft 870 supports a drillelement 880.

On account of the foregoing construction, the elongated shaft ofmicrofracture instrument 850 can be used to position drill element 880adjacent to the bone site which is to be microfractured, mount 855 canbe moved (via one or more control rods or lines 860) so as to direct thedrill element toward the bone surface, and then drive shaft 870 can berotated so as to turn drill element 880 into the bone, whereby tocreated the desired microfracture. Again, this process can be repeatedas many times as desired until the desired degree of microfracture hasbeen achieved.

MODIFICATIONS

It will be understood that many changes in the details, materials, stepsand arrangements of elements, which have been herein described andillustrated in order to explain the nature of the invention, may be madeby those skilled in the art without departing from the scope of thepresent invention.

What is claimed is:
 1. A method for applying microfracture therapy to abone, the method comprising: providing a microfracture instrumentcomprising: an elongated, substantially straight shaft comprising adistal end, a proximal end, and a longitudinal axis extending betweenthe distal end and the proximal end; a needle comprising a body having adistal end, a proximal end, and a longitudinal axis extending betweenthe distal end and the proximal end, the distal end terminating in atleast one sharp point, the needle being movably mounted to the distalend of the elongated, substantially straight shaft so that (i) thelongitudinal axis of the needle extends transverse to the longitudinalaxis of the elongated, substantially straight shaft, and (ii) the needleis configured for movement along the longitudinal axis of the needlebetween an extended position for engaging the bone with the at least onesharp point of the needle and a retracted position for withdrawing theat least one sharp point of the needle from the bone; and a drive shaftformed separately from the needle and movably mounted to the elongated,substantially straight shaft for movement along the longitudinal axis ofthe elongated, substantially straight shaft, the drive shaft having atleast one surface for cooperating with the body of the needle so thatmovement of the drive shaft along the longitudinal axis of theelongated, substantially straight shaft moves the needle between itsextended position and its retracted position; positioning the elongated,substantially straight shaft adjacent to the bone; and moving the driveshaft along the longitudinal axis of the elongated, substantiallystraight shaft so that the at least one surface of the drive shaftcooperates with the body of the needle to move the needle along thelongitudinal axis of the needle into its extended position, whereby theat least one sharp point of the needle engages the bone.
 2. A methodaccording to claim 1 further comprising moving the drive shaft along thelongitudinal axis of the elongated, substantially straight shaft so thatthe at least one sharp point of the needle disengages from the bone. 3.A method according to claim 1 wherein the drive shaft is slidablyconnected to the body of the needle such that longitudinal movement ofthe drive shaft along the longitudinal axis of the elongated,substantially straight shaft moves the needle between its extendedposition and its retracted position.
 4. A method according to claim 3wherein the body of the needle comprises an enlarged head, wherein theat least one surface of the drive shaft comprises a bifurcated needleseat, and further wherein the bifurcated needle seat engages theunderside of the needle head.
 5. A method according to claim 4 whereinthe drive shaft is spring-biased towards the proximal end of theelongated, substantially straight shaft.
 6. A method according to claim4 wherein the drive shaft is spring-biased towards the distal end of theelongated, substantially straight shaft.
 7. A method according to claim3 wherein the body of the needle comprises an enlarged head, wherein thedrive shaft comprises a drive surface set at an angle to thelongitudinal axis of the drive shaft, and further wherein the drivesurface slidably engages the top of the needle head.
 8. A methodaccording to claim 7 wherein the needle is spring-biased into itsretracted position.
 9. A method according to claim 7 wherein the driveshaft is spring-biased towards the proximal end of the elongated shaft.10. A method according to claim 7 wherein the drive shaft isspring-biased towards the distal end of the elongated shaft.
 11. Amethod according to claim 1 wherein the elongated, substantiallystraight shaft comprises a first portion and a second portion, andwherein the first portion comprises the distal end of the elongated,substantially straight shaft and carries the needle, and further whereinthe second portion comprises the proximal end of the elongated,substantially straight shaft and carries at least a portion of the driveshaft.
 12. A method according to claim 11 wherein the first portion isdetachable from the second portion.
 13. A method according to claim 1wherein the distal end of the elongated, substantially straight shaftcomprises an opening, and further wherein the needle is configured tomove within the opening.
 14. A method according to claim 1 whereinmovement of the drive shaft is limited by a stop.
 15. A method accordingto claim 1 wherein the drive shaft is moved manually.
 16. A methodaccording to claim 15 wherein the drive shaft is moved manually by meansof a handle.
 17. A method according to claim 15 wherein the drive shaftis moved manually by striking the drive shaft with a mallet.
 18. Amethod according to claim 1 wherein the drive shaft is moved by apowered actuator.
 19. A method according to claim 1 wherein the needlecomprises a plurality of sharp points.
 20. A method according to claim13 wherein the opening is disposed at an angle relative to thelongitudinal axis of the elongated, substantially straight shaft.